9, 10 and 11 year olds.
The children watched a video of Eschers tessellation work. They then made their own tessellation.
I used Holly's blog as an excellent guide for this lesson. http://linesdotsanddoodles.blogspot.co.nz/2012/01/tessellations-4th-grade.html?showComment=1372050278785
I asked the children to use traditional Maori symbols in their tessellations. Hence the korus. The areas of difficulty for some of the children was the careful positioning of the cut out on the other side. I has to be spot on to work well. Given more time I think outlining would be effective.